Entrepreneurs are hustlers. We wear many hats. We're like the chameleons of the business world, adapting to whatever we need to be at any given moment in time. It is no wonder so many of us struggle when our ventures gain critical mass and it comes time to focus our brand.

In the mind of the customer, you get to be one thing. One. That matters because the customer's mind is where your brand lives. Not in your headquarters. Not on your website. Not in your PowerPoint deck.

You don't get to be five things. You don't get to be three. If you say you are three things to your customer, you are saying you are nothing. If you say you are three things that your competitors already say they are, you are saying you are less than nothing.

Your one thing is the unique value that your brand delivers. Volvo keeps you safe. IBM is building a smarter planet. 7-Up is the uncola.

Your customer doesn't care what you want to be. They simply walk through life and perceive things. They don't perceive you a certain way because they're being difficult. They're doing it because they are humans and that's what people do. Just like people make impressions on other people, so do companies.

It's very tempting to try to be everything to everyone. You might make some sales in the short run by doing that. But in the long run, you sacrifice the impression your brand makes on the collective consciousness of your potential customer base.

Positioning is the art of sacrifice -- of sacrificing the things you could be to uncover the one thing you should be.

I know what you're going to say next: "But we do more than one thing! We have more than one kind of customer!"

You think IBM doesn't?

That's OK. Your one thing is a prism, not a box. That one thing may be translated differently across different lines of business or different customers, but at the end of the day, those messages should all ladder up to a single value your company provides.

What makes a powerful one thing? Use this four-point litmus test to make sure your core message will work:

First, your core message needs to have an emotional and rational side. You need to connect with people's hearts and minds. Make no mistake. People are driven by both. A simple idea like "Volvo makes cars that are safe" resonates on both levels.

Second, it needs to be believable. I could tell you: "Adam is the next President of the United States." But wish me luck convincing you of that.

Third, your core message needs to be relevant to a group of potential customers. If there's no market opportunity, that's not a good place to be. I might own the only lemonade stand on Mars -- a great positioning opportunity -- but not if there are no thirsty Martians to drink my lemonade.

Fourth, your core message needs to be simple. If people can't understand, remember or repeat your one thing, it's too complicated. If it's too complicated, it won't find a home in your prospect's mind. And remember: that's where your brand lives.